Individual skill
exploiting-cross-site-script-inclusion-xssi
Identifying and exploiting Cross-Site Script Inclusion (XSSI), where the script tag's exemption from the Same-Origin Policy lets an attacker include a victim endpoint cross-origin (with the victim's ambient cookies) and read sensitive data from static scripts, dynamic JS, JSONP responses, or non-JS files (CSV) included as scripts. Activates when assessing endpoints that return JS/JSONP or data reachable via a script tag.
internal/tools/skills/data/web-application-security/exploiting-cross-site-script-inclusion-xssi/SKILL.md
Source commit d42f381ad34843e71a42658e5c57290c713e85af
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- Matches the observed repository HEAD
- Yes
- Scanner rules are current
- Yes
- Repository scan complete
- No
- Skill scan complete
- No
- Observed behavior
- Network or broad shell
- Last checked
- Nov 9, 2026
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Repository context
- Repository stars (not skill ratings)
- 1,320
- Repository last updated
- Nov 8, 2026
- License
- Apache-2.0
Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.
- cybersecurity Repository topic
- security Repository topic
- bug-bounty Repository topic
- automation Repository topic
- autonomous-pentesting Repository topic
- ai-agent Repository topic
- ai-security Repository topic
- ethical-hacking Repository topic
- golang Repository topic
- penetration-testing Repository topic
- penetration-testing Declared skill tag
- xssi Declared skill tag
- jsonp Declared skill tag
- owasp Declared skill tag
- web-security Declared skill tag
- data Derived category
- security Derived category
- testing Derived category
- security-application Derived category
Files and excerpt
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Read excerpt
# Exploiting Cross-Site Script Inclusion (XSSI)
## When to Use
- During authorized assessments of endpoints that return JavaScript, JSONP, or data consumable via a `<script>` tag
- When an authenticated endpoint embeds user-specific data into a JS file or global variable
- When the application exposes a JSONP callback parameter (`?callback=`, `?jsonp=`)
- When sensitive data (CSV, JSON) is served with a permissive `Content-Type` and no anti-inclusion guard
- When evaluating whether endpoints rely on cookies (ambient authority) and lack CSRF-style tokens or CORB/CORP
## Prerequisites
- **Authorization**: Engagement scope covering cross-origin data disclosure with a logged-in victim test account
- **Attacker-controlled origin**: A page you host to include the victim script and capture leaked data